Table 2. Comparison of sulfadiazine (SDZ) and sulfamonomethoxine (SMM) oral pharmacokinetics in Holstein cows (n=4) after their intravenous (5 mg/kg BW) and oral administration (10 mg/kg BW).

Parameters	Units	SDZ	SMM
		Mean ± SD	Mean ± SD
ka	hr−1	0.158 ± 0.029	0.179 ± 0.023*
t1/2ka	hr	4.51 ± 0.82	3.91 ± 0.51*
kel	hr−1	0.262 ± 0.027	0.433 ± 0.058*
t1/2kel	hr	2.66 ± 0.25	1.62 ± 0.24*
Cmax	µg/mL	7.01 ± 0.50	4.29 ± 0.32*
Tmax	hr	5.00 ± 1.15	2.75 ± 0.96*
F	%	85.7 ± 2.7	89.5 ± 7.3
MAT	hr	5.92 ± 1.11	5.24 ± 0.69*
MRTi.v.	hr	3.69 ± 0.32	2.21 ± 0.31*
MRTp.o.	hr	9.61 ± 1.27	7.45 ± 0.66*
AUCi.v.	µg/hr/mL	52.0 ± 6.5	25.1 ± 3.0*
AUCp.o.	µg/hr/mL	98.5 ± 13.1	45.6 ± 6.0*
CLtot	L/hr/kg	0.0973 ± 0.0118	0.202 ± 0.023*
Vdss	L/kg	0.357 ± 0.027	0.445 ± 0.081

ka=primary absorption rate constant; t_1/2ka=absorption half-life; k_el=primary elimination rate constant; t_1/2kel=elimination half-life; C_max=maximum blood concentration; T_max=time to maximum plasma concentration; F=oral bioavailability percentage; MAT=Mean absorption time; MRT_i.v.=average residence time during intravenous administration; MRT_p.o.=average residence time during oral administration; AUC_i.v.=area under the plasma concentration-time curve after intravenous injection; AUC_p.o.=area under the plasma concentration-time curve after oral administration; CL_tot=total body clearance; V_dss=distribution volume at steady state.